Automatic means for changing timing intervals



Aug. 30, 193.2. H. H. HAGLUND 1,874,187

UTOMATIC MEANS FOR CHANGING TIMING INTERVALS Filed Dec. 4. 1930v 6 Sheets--SheerI l l l i g 8 l In s v l i' mmm 01, m l Emnmunw L immuun In (I) 3mm/tm H. H. HAGLU ND ya om 33M au Wcmw Aug. 30, 1932. H. H. HAGLUND 1,874,187

AUTOMATIC MEANS FOR CHANGING TIMING INTERVLS Filed Deo. 4, 195o s snets-sheet 2 @nvm/woz H'. Hl HAGLU ND Aug. 30, 1932. H. H. HAGLUND 1,874,187

AUTOMATIC MEANS FOR CHANGING TIMING INTERVLS 5 sheets-sheet s Filed Dec. 4, 1930 ...L-O.: .=m

H H. HAGLUND Patented ug. 30, V1932 UNITED SFIATISSv PATENT OFFICE" IIAKON' H. HAGLUND, OF FLUSHING, NEW YORK, ASSIGNOR TO WESTERN' UN'ION TELEGRAPH COMPANY, F NEW YORK,

N'.Y.,- A CORPORATIONv 0F NEW YORK AII'JTOMA'JZIC MEANS IOR CANGINGYTIMIN'G; INTERVAKS applicationr nea neeembera, 1930.V serial No. 560,106.

, rlhis invention relates to automatictelefj graphic transmission over transmission lines and more particularly to'mechanisrn for ,determining the periods of reversal of thedirectionV of signaling `over 4submarine cables. rlhe present day developments`,in the eld of loaded Vsubmarine cables, ,have madet'it possible to employ cables having electrical characteristics which, permit' of a speed of lo operation far in excess of any speed used heretofore over unloaded cables. At such high operating speeds diliculty is experienced howeverV in constructing andl adjustingan artificial line which willfsimulate the 'real cable with suicient accuracy to permit dupleX operation at the possible speeds of transmission over thecable and in some installations it has been the practice to operate the 2G cable in one direction only at a time and to provideV some means for automatically rfeversing the direction of Vtransmission, at frequent intervals.

In Patent":#:1, 81,489 granted ,Auguist2l`1, v

1928, to Locke and Haglund, such a'system for automatically reversing; the direction of transmission over'the cable at periodic'intervals, by means of timing devlces located at each station, is disclosed. In this patent,the reversing!v mechanism consists brieily ot a series of switch actuatingcams, driven by a friction clutch i fromv an electric motor throughan escapement mechanism. The timing device comprises a second series of switch operating cams, driven at diiferent speeds through reduction gearing from therotary distributor, the timing `device serving irst to complete a`circuit, tostart the driving motor of the reversing mechanism just prior tothe time ofreversing the direction :of transmission, then to complete a pulsing circuit for the escapement magnet of the revers ing mechanism at the exact predetermined switching time and finally to interrupt the motor circuit after the transmitting circuit connections have been reversed;

The timing cams are arranged sothalt they complete a cycle, that is, make a lcomplete revolution in about twelve minutes. The 50 traiiic, conditions do not` remain constant throughout the day butv are continuously of the equipment at one or the other of t changing so that at certain periods there may, be a much'greater demand for traic in one direction lthan in the lother and at other' periods, the bulk of the traiic may be in the y e opposite direction.A To meet the require- Inentsjof vsuch changing :traino conditions, a

number of timing cams may be provided, coded to different periods of transmission in each direction. For instance, one cam ma provide for transmission one minute east an' one minute west; another may provide for transmission two minutes east and one minute west, another, one-minute east Vand three minutesnwest, etc.`V The cams are arran edV so jthat any vcam may be manually selecte to control vthe lperiodsof transmission in each direction. A precision timing cam deter- I nines the exact time of reversing the circuit connections.

With the system set forth in the Locke `Haglund patent, whenthe cable dispatcher desires to changethe period 'of transmission or timing interval, a message is sent out from one station instructing the operator or 'attendantfat each Vof the terminal and-repeater stations to manually change from one timing ca m to another designated one. The change must `be made within the same minute at every cable station concerned, the instruc- ,-o

tionsusually specifyingthe change to be made at the next zero, that is, at theV end of the twelve minute cycle. i

Since the message orderin be received several minutes position` is reached, the attendant'in charge e stations may become occupied with other work and consequently forget to make the the change ma `change atthe proper moment. VThis causes t the stations to lose synchronism and delays starting up the circuit again It is one of the objects ofthe present invention to overcome this difficulty and to provide a timing mechanism which is semiautomatic'` in character, that tis, in which means may be set manually during anyportion of the cycle for automatically changing `the control from cam to anotherat the end of the cycle. v,

efore the zero 1 t Another object is to maintain the timingiioo cam. Whenever a change is to'be effected in the timinginterval, the auxiliary cams serve to actually raise one of the cam followers from its timing cam and to lower another of the cam followers on to its timing cam at the end ofthe cycle. The auxiliary cams may be set manually at any time during the period of revolution of the Vtiming cams, that is, immediately upon receipt of the dispatchers message, but will not be effective to make the transfer until during the last minute of the cycle.

V,The timing vcams are preferably rotated through reduction gearing by an electric motor, the speed of which is accurately maintained in direct relation to the speed ofthe transmitting distributor, by; electrical impulses produced by a local ring of the distributor., Y

The invention will be more fullyunderstood `by reference to the accompanying drawings in which:` l

' Figure 1 is a plan view of a timing mechamism embodying the present invention; p

Figure 2 is a front elevation thereof;

Figure 3 is a perspectiveV View showing two ofthe timing cams and their auxiliary Cams and-Cam followers;

Figure 4 is a sectional view on the line 4- 4 of Flgure 1, showing another of the timing cams;

Figure 5v is a side elevation of the main operating clutch for starting the operation of the cams, in unison' atv each station;

*Y Figure 6 is an elevation view of one of the timing cams, showing the auxiliary cam positioned so as to raise the camy follower at the end of the cycle;

Figure 7 is an elevation view, showing the auxiliary cam arranged to lower the cam follower on to the timing cam. at the rend of the cycle; A

Figure 8 is an elevation View, showing the relative position of the timing and auxiliary earns of Figure 6, at the end of the cycle; and v Figure 9 is a diagrammatic view of the timing mechanism and circuit reversing mechanism. u

Referring first to Figure 9, I have shown the timing mechanism diagrammatically, as consisting ofa series of six cams, 10, 1l, 12,

13, 14 and 15, rigidly mounted upon a common shaft 16, driven preferably at a speed of onetwelfth R. P. M. through reducing gearing 17, and a ratchet clutch 18, from a combined D. C. and A. C. motor 19. Each cam is provided with a cam follower adapted, when the follower engages a depressed portion of its cam, to close its associated contact. The cams are each provided with a different arrangement of raised and depressed portions whereby as the cam shaft revolves at a uniform rate each of the switches 22 to 27 may be Vclosed at different intervals. Cam 10, for instance, is coded so as to close the switch 22 once each minute, to control the reversing mechanism, indicated generally at 28, to effect transmission one minute east and one minute west. Cam 11 eifectstransmission one minute east and two minutes west, cam 12 is coded for transmission two minutes east and one minute west, cani 13 two minutes east, two minutes west, cam 14 one minute east and three minutes west and cam 15 three minutes east and one minute west. Obviously, other arrangements may be provided, the above being shown by way of example only. It is obvious, of course, that the period of revolution' of the cam shaft is not restricted to twelve minutes, this period being chosen merely for convenience in subdividing the different periods of transmission in each direction.

Each of the cam followers is extended to also engage auxiliary cams 29 to 34, individual to each timing cam, each of the auxiliary camshaving one-half of its periphery raised and the otherhalf depressed. The cams 29 to 34 are mounted on a common shaft 35 (Figure 1) and may be manually rotated thereon so as to position either the raised or recessed portionthereof beneath the end of its associated cam follower. With the auxiliary cams in the position shown in the diagrammatic view, the cam follower for timing cam 10 is free to follow the contour of the cam, so as to close the switch 22 twelve times during each revolution. The cam followers associated with the remaining timing cams are held free of the timing cams so that the switches 23 to 27 remain open as the cams revolve.

The seventh timing cam- 36, which may be termeda precision cam, is also driven from the motor 19 through reduction gearing 37 and is geared so as to close its associated switch 38 at frequent intervals, as for instance every fifteen seconds.

The angular position ofthe cam 36 on its shaft, relative to the cams 10 to 15, is such that during each period of closure of one of the switches 22 to 27, switch 38 will also close. The switches 22 to 27 are. all connected in parallel with each other and in series with theswitch 38 so that upon the co-incident closure of the switch 38 and one of the switches 22- to 27, a` circuit will be completed from the ground, at switch 38, through foneA ofA the switches 22 to 27 and by conductor 39 to an escapement magnet 40 and thence by' brushes 41 and 42 and commutator drum 43, to a source of potential 44. The commutator drum 43 has a 180.'o sector 45 insulated from the remainder of the drum whereby, as the drum revolves, the brushes 41 and 42 will be bridged during each vhalf ,Y

revolution only, thereby supplying impulses to the escapement magnet 40. The escapement magnet controls an escapement wheel 46 carried on a shaft 47 driven bya spring motor 48 and having a `series off cams 49, 50, and 51, the function ofwhich -is-tov reverse the circuit connections lof the cable receiving 'apparatus transmitting and through the switches 52, 53 and 54, so as to periodically reverse the direction oftransmission, asis fullyset forth in the aforesaid' Locke-Haglund patent.

One of the calms 55, on shaft 47 serves to complete a locking circuit for the escapement` magnet 40,as'soon as the shaft 47 advances. one step. The cam` 55 has two short depresfV for the escapement magnet, whereby t-hel magnet continueslto step irrespectiveof the position of the timingcams,by the impulses supplied by the commutator 43, until the shaft 47 has moved through 180o from its starting point, at which time the escapement magnet and the shaft stop, due to the opening of the switch 56, as the opposite cam depression comes into position beneath the .cam follower. The angular position of the timing cams is such that the pulsing circuit through these cams opened while the shaft 47 was rotating through the 180. V i

The alternating current side 57, of the motor 19 is supplied with alternating impulses i from the secondary winding of a transformer 58, the primary winding of which has one terminal connected to the odd numberedsegments of a pulsing ring 59, on the face plate of the transmitting distributor Tl) and the opposite terminal connected to the even num-v bered segments of ring 59. The solid ring 60 is connected to battery of one polarityand the mid-portionof the primary winding is connected to battery of the opposite polarity, whereby as the brush 61 sweeps'` over the rings 59 and 60, current alternations of a fre` quency having a definite relation to the speed of the rotary transmitter,will be induced in the'seeondary winding, for accurately con-JV trolling the speedof the motor L19; Thedi-A rect current side 62 of the motor is driven from a battery 63 through resistance 64, the' field winding 65 of the motor being connected in shunt to the battery.

In the position-shown, of the reversingl mechanism 28,` the `line V:L""is connected i throughthe upper contact of switch 54 di-V rectly to the.receivingrelaythe tongue of which! repeats the receiving slgnals through the receivingrings RD to the printer- (not shown), theprinter eircuitbeing corfnpletedl to ground through the-.switch 52.l When a reversalof the mechanism-28 occurs, the ire'- ceiving relay is disconnected from the line at the switch 54 anda circuit for thetransmitting apparatus completed .i fromr ground `through'iswitch 53, to vpositiveor-` negative battery B, transmitter contactsfand transmitting rings TD, thence by the lower contact of switch 54 to the'line L. The printer is disconnected at this ftimevat contactf52.

`.The operation of vthe timin mechanism having been described with re eren'ce to the di agrammatic' view, the specific 4construction of theftimingmechanism will now be described in connection .withFigures 1 to28.

Mounted upon asuitablebase is the motorj 19, having a sha1-ft 66 which, :through a worml 67 and gear 68, drives a shaft 69 journalled in vbearings 70 and 71 land having a ratchet clutchmember" 7 2 rigidly secured to itsex-` tremeleft end (Figure 1),. 'lhecommutator drum 43'is carried by the shaft 69.

Clutchfmember 72engages with `al driven clutch member 7 3,-1w-hich'- is'keyed to a shaft 74"and` 'is slidable axially thereof. The` clutch members 72 and 73iare normally held: in er'ig'agementbyA 'a spring-`7 5 disposed between the'clutch member 73anda fixed abut-lY ment'76,'onithe shaft 74. A magnet 77 (Fig ure 5)l is mounted beneath theclutch member and the `hooked ,end ,of itsvairmature 78 'eX tends through an opening 79 in a pivoted lever. 80, having'a'yoke extending intoan annular recess' 81 formed in the clutch v member 73. The outer'hooked end ofthe armature i` 78 is i urged "upwardly by a Vspring 82` and when" 'the `clutch is manually disengaged, serves to latchthe same insuchdisengaged position thereby disconnecting the motor -19 from 'the cam shafts ,lto be subsequently described. The function of the clutch 72, 7 3 'is' topermitthetiming cams to be set manually in the same -position'at all stations and to be started into Voperation simultaneously at each station, by operating thezmagnet 7 7, in response to atransmitted signal.

The shaft 74 is journalled in bearingsf83 and 84 and isprovided with a knurled knob 85, whereby the shaft may be manually rotated independently of the lmotor 19.` A vworm 86, on the shaft 74,l meshes with'a gear 87, loosely mounted upon ashaft;88, journalled in bearings 89 and 90. The gear 87 drives the shaft 88 through a ratchet clutch 91, the driven member 92 of which is pinned to the shaft 88, the drivi member 93 being loosely mounted thereon or both rotative andsliding movement. The clutch members 92, 93 are `normally held in engagement with each other by a spring 94 coiled about the shaft 88'and disposed within a hollow recess in the key member 9.5 secured to the gear andengagingwith the slotted extension96- of theA clutchmember 93. The clutch 91 permits the shaft 88 to lbe rotated independently of the shaft 74,.by means of a hand knob 97.

In the specific embodiment shown the shaft 88 is geared to operate ata speed of four R. P. M. and the timing cam 36,' which for convenience may be termed the fifteen second cam, is secured to the shaft 88 and serves to close the switch 38 once each revolution thereof. 1

v The cam shaft 16 is driven from the shaft 88 at a reduced speed through the worm 98 and a :gear 99 (Figure 2) andthrough la clutch 100 vof the same construction as'the clutch 91. Shaft 16 is journalled in bearings 101 and 102 and is provided .with a hand knob 103 for adjusting the angular position of the camshaftkrelative to shaft 88, whereby the coded timing' cams 10 to 16, mounted thereon, may be correctly positioned with respect to the precision timing cam 36. .The cams 10- to 15 are secu-red to the shaft 16 to rotateV therewith, preferably at a speed of one-twelfth R.V P. VM. at the 'normal signalling' speed. Brackets 105 and 106 are disposed at the opposite ends of the group of cams 10 to 15 and carried-between these brackets and arranged parallelto the shaft 16 is the shaft 35, upon which the auxiliary cams 29 .to34 are mounted for independent ro. tation.' Each of the auxiliary cams has an operating disk 107 integral therewith by which the cam may be manually rotated into the desired position. The shaft 35 is drilled radially at 108 (Figure 7) beneath each of the auxiliary cams and is provided with spring pressed ball detents 109 arranged to engage. inany of the four depressions 110 to 113, in the bore of each ofthe auxiliary cams, to hold them in any one of four predetermined positions.

Also extending between the brackets 105 and 106 and journaled therein is a shaft 114,

having a longitudinally extending key 115. The individual cam followers 20are mounted on the shaft 114 and have recesses 116 in their hubs somewhat larger than the key 115 so that they have limited rocking movement on the shaft. 1 Y

Each cam follower is pressed into engagement with its timing cam or auxiliary cam by a spring 117 carried by a bar 118,r extending between the bracket members105 and 106. The cam followers are provided with insulated proj ections 119 and 120, the former being arranged to engage with the timing cam and the latter to engage with the auxiliary cam.

The shaft 114, outside the bracket 106 has a switch arm 121 adapted to operate a pair of switch contacts 122 and 123 through a pin 124. Contact spring 123 is biased to open position, towards the arm 121.

With the auxiliary .cam 29 set as shown in Figure 3 and with the remaining auxiliary cams set in the position of auxiliary cam 30, the timing cam 10 alone will be effective for controlling the periods of reversal of transmission. As lthe cam 10 rotates the raised portions of its periphery rockthe cam follower upward permitting the shaft 114 to rotate counterclockwiseunder the pressure of the contact spring 123 to open the contacts. When a depression in theV cam 10 comes opposite the projection 119 of the cam follower, the shaft 114 is rocked in a clockwise direction under the pressure of spring 117, to close the switch contacts against the pressure of spring 123.

The key and slot construction permits the switch contacts to be operated by any one of the cam followers whenever the remaining cam followers are held free of their timing cams, whereby the single switch takes the place of the group of parallel switches 22 to 27 shown inthe diagrammatic view of Figure 9. The contacts 122 and 123 are connected in series with the contacts of switch 38 associated with the precision cam 36 and with the escapement magnet 40 and commutator brushes 41 and 42, to supply the first stepping impulses to the escapement magnet.

With the construction so far described, in order to change the periods of reversal of transmission, it is necessary to set the auxiliary cams by hand, just at the end of a designated cycle. iary cams may be manually set at any time during the cycle and automatically brought into operation to change the timing intervals at the end of the cycle, each auxiliary cam operating disk 107 is provided with two diametrically opposite bars 125 and 126, and each vof the timingcams is provided with a pin 127, (Figures 6, 7 and 8) adapted under certain circumstances to engage the bar 125 0r 126, to rotate its auxiliary cam into the proper position for controlling the operation of its cam follower.

Assume by way of example that the timing cam 10 is controlling the periods of reversal and it is desired, at the end of the cycle, to change over to timing cam 11. Immediately upon reception of instructions to this effect the vauxiliary cam 29 may be rotated by hand to the position shown in Figure 6, that is, with the bars 125 and 126 extending nearly horiln order that each of the auxilfio Zontal and `with thebar' 125 Tprojecting intov -their set, position. As the timingca-m continuesto rotate and duringv the last few ldegrees of its rotation, lthat is just at `theend ,of the cycle, the pins 127, on the cams 10A and V11, engage the'barsr125 and 126 ofthe auxiliary cams 29 .and 30, respectively, and rotate the auxiliary cams. such a distancefthatthe cam 29V assumes the position shown in Figure y8, with the 'raised portion thereof beneath -the camk .follower .and cam 30assumes the diametrically oppositeposition, with thev depressed portion of thecam beneath the cam follower. The' follower of timingcamflOis thus rendered ineffective tofurther control the switchcontacts 122, 123 and the follower of timing cam 11 is lowered into contact with its timing cam whereby itrwill be operated by subsequent rotation of the'camllgto control ,the periods of ,reversal of transmission.

In the same manner any of the auxiliary cams may be set at any period during the cycle, as immediately upon the receipt of the despatchs orders and the actual transfer` will take place simultaneously andl automatically ateach cable stationatA the end ofthe cycle. Obviouslyvarious modifications may be made in the construction and'operation ofthe -timing mechanism and the automaticcontrol thereof and :I `donot desireyto .be limited tol the specific arrangement shown and described. Y v, 1 i Y ."WhatIclaimis: .A

. 1. A timing mechanisinwfor .controlling the period of transmissionin each direction -over a; transmission line 'comprising a plu- -ralityof cams, switchmeans controlled by -aV selected one of said cams,. each of esaid Vcams being coded so as to operate said switch means at differently Atimedintervals and means for automatically changing the'control from one cam to another." A Y V2. A timing mechanism 'for controlling the period of transmission inleach direction over a transmission lineV comprising, switch means, a plurality of switch operating means `having a predetermined lcycleof operation and individually coded to actuate said switch lmeans at differently timed, Zintervalsfand means adapted to be positioned at anytime during a cycle for automatically changing the control from one switchoperating means .tofanotherg'at a predetermined later period --inthe'cycle y '1 f y.

Atiming mechanism forvcntrolling the period of transmission,` in each direction over "a transmission line y. comprising a vplurality of cams having a predetermined cycle ofoperation, switch means controlled by said individual cams, each ofsaid cams being coded to operate` said switch means at rdifferently timed intervalsand means adapted to be positioned at any time during alcycle for-11,11#` 'tomatically changin'gethe controllfrom one cam to another at a predetermined laterperod in 'the `cycle. Y c Y `4.v A timing mechanismfor controlling the period of; transmission in each directionlover a y transmission line comprisinga' plurality of cams,f c' am followers `individual to each c am, -switch means controlled i bysaid individual -cam followers, each of said cams being coded toop'erate said switch means atdifeiently timed intervalsfandmeans adapted to be positioned at any timel during'a cycle for au-l tomatically engaging said cam followers at a. subsequent period' in saidcycle,- forgchang- ,ingthe control from one cam to'another. Y

Y 5. A timing mechanism forcontrolling the reversal of directionoftransmission over fa' l transmission line periodically, comprising a plurality of i timingl 'cams codedv for, differ- -ent Vperiods ofreversal, a cam follower for each` cam, means controlled by the individual "cam followers for. eife'ctingnreversal of di-V rection of transmissiomfan-` 'auxiliarycam associatedwith each cam follower and means "for 'individually positioning y said, auxiliary -cams,- sothat, at a definitey point Ain the rota- -tion .of said timing cams the auxiliary cams "will be actuated to' hold certain of said cam followers free from contact Awith said timing gcamsand to permit another of said cam folg lowersito move intofcontact with one L of said Mtiming cams` f 6. A timing mechanism for controlling -thereversal of direction of transmission Vover a transmissioriline periodically comprisinga plurality of timing camscoded for different 'periods :of reversal, a cam follower foreach \cam, means controlledby the vindividual followersfor effecting reversal of direction of ,transmissiom van auxiliary cam .associated 'with'each Vcam follower, eachof saidauxilyiary cams having a position 'inc whichit 'holds its associated. cam follower out of engagement with its timing cam and means operatingk at a predetermined point inthe l cycle of operation of the timing cams 4for moving said auxiliary camfrom such posi-4 -tion into a position to 4permit the cam follower to follow the contour of its timing cam. 7. A timing mechanism for controlling the rreversal of direction of transmission ovei` a transmission Tline `Vperiodi `zally comprising a plurality of timin cams coded for different periods of' reversa a cam followerforeach cam, means controlled by individual followers for effecting reversal of direction of transmission, ;an 'auxiliary f f associated with operating at a predetermined point in the s Vcycleof operation of said timing cams for moving said auxiliary cam, when it is in one VVVof said positions, into a position to permit the cam follower to follow the contour of said timing cam.

8.- A timing mechanism for controlling the reversal of direction of transmission over a Atransmission line periodicallycomprising a plurality of timing cams coded for different periods of reversal, a cam follower for each i l line, of signal transmitting and receiving apcam, means controlled by individual followers for effecting reversal of direction-of trans- Vmission, an auxiliary cam associated with each cam follower, each of said auxiliary cams having at least two positions in which it holds its associated cam follower out of `engagement with its timing cam and at least two positions in which it permits the cam follower to follow the timing cam and means operating at a predetermined point in the cycle of said timing cam for moving said auxiliary cam, when it is in one of said first two positions, into a position to follow the cam and, when it is in oneof saidsecond two positions, to hold the cam follower out of contact with its timing cam.

9. Ina telegraph system employing rotary transmitting and receiving apparatus, circuit reversing meclianism, timing mechanism for controlling the operation of said reversing mechanism, a driving motor for said timing mechanism and means including a vsegmented ring of said rotary apparatus, for Amaintaining a definite speed relation between the timing mechanism and said rotary apparatas.

10. In a telegraph system employing rotary transmitting and receiving apparatus, circuit reversing mechanism, timing `mechanism for controlling the operation of said reversing mechanism, said timing mechanism comprising a plurality of cams differently coded and switch means` actuated thereby, means for rotating said cams in definite speed relation with respect to said rotary apparatus and means for selecting, at one period in the revolution of said cams, the particular cam which will be effective to control said reversing mechanism at a later period in the revolution of said cams.

11. In a telegraph system employing a rovtary transmitting vand receiving apparatus,

circuit reversing mechanism, timing mechanism for-controlling the operation of said reversing mechanism, said timing mechanism Vcomprising a plurality of cams differently coded, a driving motor for said cams and --switch means actuated b individual cams, lmeans controlled by sai rotary apparatus for supplying pulsating current to said motor to maintain a definite speed relation between said cams and rotary apparatus and means for automatically changing the control from one cam to another.

12. In a telegraph system employing rotary transmitting andl receiving apparatus, circuit reversing mechanism, timing mechanism for Vcontrollingthe operation of said reversing-mechanism, a driving motor for said timing mechanism and means controlled by said rotary apparatus for supplying pulsating current to said motor to maintain a definite speed relation betweenV said cams and vsaid rotary apparatus.

13. The combination with a transmission paratus at-each terminal, means for connecting said transmitting and receiving appa- -ratus to said line alternatively comprising `switch mechanism, van escapement for controlling'the operation ofsaid switch mechanism, a timing mechanism maintained in synchronism with the message signaling impulses and a pulsator driven by said timing mechanism for periodically operating said escapement mechanism to reverse the line connections.

14. The combination with a transmission line, of signal transmitting' and receiving apparatus at each terminal, means for connect-v .ing said transmitting and receiving apparatrical impulses to thestepping mechanism' from saidl commutator, to reverse the line connections.

15. The combination with a transmission line, of a rotary signaltransmitting and receiving apparatus at each terminal, Ameansv for connecting said transmitting and receiving apparatus to said line alternatively comprising lswitch mechanism, a stepping device for actuating said switch mechanism, a,

timing mechanism, a driving motor for said -timing mechanism, means controlled by said rotary apparatus for supplying pulsating current to said motor to maintain a definite speed relation between the timing mechanism and said rotary apparatus, a commutator driven by said timing mechanism and switch means actuated by the timing mechanism for supplyingelectrical impulses to'said stepping mechanism fromy said commutator, toV

reverse the line connections.

16. A timing mechanism for controlling the period of transmission in each direction Y over a transmission line comprising adriving shaft, a precision timing cam and a plu-A... rality of' differently *coded timing cams,'

llao

means including said precision'cam and one of said coded cams for reversing the direction of transmission periodically, means for automatically changing the control from one of said coded camsA to another at a predetermined period and means for varying the i relative position of said driving shaft precision cam and coded cams.

17. A timing mechanism for controlling the period of transmission in each direction over a transmission line comprising a driving shaft, a precision timing cam and a plurality of differently coded timing cams, means including said precision cam and one of said coded cams forreversing the direction of transmission periodically, means for automatically changing the control from one of said coded cams to another at apredetermined period and manual means for independently varying the relative position of said precision cam and coded cams relative to each other and to said driving shaft.

18. A timing mechanism for controllingthe periods of transmission in each direction over a transmission line .comprising a driv-v Y ing shaft, a precision timing cam, a shaft therefor, a plurality of differently ;coded timing cams, a shaft for said coded cams, means including said precision cam and one of said coded cams for reversing the line connections, means for changing the control from one of said coded cams to another and an individual ratchet clutch for each of said cam shafts for driving the same, said clutches enabling said cams to be manually adjusted relative to each othery and to said driving shaft.

In testimony whereof I afix my signature.

HAKON H. HAGLUND. 

